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The abaA homologue of Penicillium marneffei participates in two developmental programmes: conidiation and dimorphic

A R Borneman1, M J Hynes, A Andrianopoulos

  • 1Department of Genetics, University of Melbourne, Victoria, Australia 3010.

Molecular Microbiology
|December 21, 2000
PubMed

Insights

The Penicillium marneffei abaA gene regulates both filamentous growth and yeast-form development. This transcriptional regulator is crucial for cell cycle events and morphogenesis in this dimorphic fungus.

Area of Science:

  • Medical Mycology
  • Molecular Biology
  • Fungal Genetics

Background:

  • Penicillium marneffei is a dimorphic fungus, existing as hyphae at 25°C and yeast cells at 37°C.
  • Dimorphism in P. marneffei involves distinct developmental pathways: asexual reproduction (conidiation) and a hyphal-to-yeast transition.

Purpose of the Study:

  • To investigate the role of the abaA gene, a homologue of Aspergillus nidulans abaA, in the dimorphic development of Penicillium marneffei.
  • To determine if abaA regulates both conidiation and the hyphal-yeast switch.

Main Methods:

  • Cloning of the P. marneffei abaA gene.
  • Targeted gene deletion to create abaA mutant strains.
  • Complementation studies using A. nidulans abaA.
  • Analysis of gene expression during developmental transitions.

Main Results:

  • Deletion of abaA disrupted conidiation at 25°C, leading to aberrant conidiophores.
  • The abaA deletion strain failed to undergo proper hyphal-to-yeast transition at 37°C, with multinucleate yeast cells.
  • A. nidulans abaA could complement both developmental defects in P. marneffei.
  • Ectopic overexpression of abaA caused anucleate yeast and multinucleate hyphae.

Conclusions:

  • The abaA gene is a key regulator of both conidiation and the hyphal-yeast dimorphic switch in P. marneffei.
  • abaA appears to control cell cycle events and morphogenesis in these distinct developmental programs.
  • Conserved function of abaA across different fungal species highlights its fundamental role in development.

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